Currently, solar power is a relatively new renewable energy. Solar silicon wafers are indispensable components for solar cell arrays. Screen stencil printing technology is the commonly used production process of the electrodes in the industrialized manufacturing process of crystalline silicon solar cells. The double printing process is an advanced production technology, in which the front surface electrode is produced by the following steps in order, i.e., primary printing of the front surface electrode, drying; secondary printing of the front electrode, drying, sintering, and the process is completed. The secondary printing is to overlap the fingers printed by the primary printing by printing the fingers once again. Thus, the fingers can be thickened, the broken fingers can be eliminated, the effect of series resistance is reduced, and the efficiency of battery is effectively improved.
However, the existing double screen stencil printing of solar cell prints the front surface fingers (DP1) in the primary printing, and subsequently prints the busbars and fingers (DP2) in the secondary printing. As a result, the busbars are printed only once. An insufficient height will lead to the risk of unqualified tensile force of the positive electrode. If the silver paste formula is modified to have the property of high tensile force and strong corrosivity, although the tensile force can be improved, the efficiency will decrease. If the screen stencil parameters are adjusted, the height of the busbars can be improved to ensure the tensile force of the positive electrode. However, the consumption of silver paste will increase, such that the production costs will go up.
Regarding the dual screen stencil printing of solar cell, how to improve the tensile force of the positive electrode without significantly increasing the production cost or reducing the efficiency of the solar cell is an important issue that needs to be solved urgently and is critical for the development of solar cell.